1. Field of the Invention
The present invention relates to a method for manufacturing a hydrogen separation membrane fuel cell.
2. Description of the Related Art
Some fuel cells, known as hydrogen separation membrane fuel cells, have in their anode layer a hydrogen separation membrane selectively permeable by hydrogen, and thus supply only hydrogen from hydrogen-containing gas to an electrolyte. For example, Japanese Patent Application Publication No. 2006-12467 describes a method for manufacturing a hydrogen separation membrane fuel cell in which an electrolyte membrane is formed on a surface of a hydrogen separation membrane base.
In general, an electrolyte membrane is formed at high temperature. Thus, if an electrolyte membrane is left at low temperatures after being formed, an internal stress (tensile stress) may be generated in the electrolyte membrane due to shrinkage of its crystal. In addition, the thermal expansion coefficient of a hydrogen separation membrane base is often higher than that of an electrolyte membrane. It is thus known that the hydrogen separation membrane expands in a direction generally perpendicular to the moving direction of hydrogen during use of the fuel cell. Thus, an electrolyte membrane formed on a hydrogen separation membrane tends to be subjected to a tensile stress generated at an interface with the hydrogen separation membrane base during use of the fuel cell.
If such internal stresses become larger than the strength of the electrolyte membrane or the bonding strength with the hydrogen separation membrane, the electrolyte membrane may crack to cause short-circuiting between electrodes, or the electrolyte membrane may be otherwise damaged, for example with the hydrogen separation membrane peeled off from the electrolyte membrane.